Artificial turf free of infill material

ABSTRACT

An artificial turf system for installation over a receiving surface is described. The artificial turf system comprising: a sheet member made of a flexible material, the sheet member defining a first surface for interfacing with the receiving surface and a second surface; primary yarns made of straight fibers backstitched in and threaded through the sheet member and upwardly extending from the sheet member to a first elevation; and secondary yarns made of textured fibers backstitched in and threaded through the sheet member and upwardly extending from the sheet member at a second elevation less than the first elevation which is caused by a difference in texture between the primary yarns and the secondary yarns, wherein the secondary yarns are more rigid than the primary yarns, and wherein the primary yarns and the secondary yarns have ends which are cut after being threaded through the sheet member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of and claims priority from U.S. patent application Ser. No. 16/551,635 filed Aug. 26, 2019, which is a continuation-in-part of and claims priority from U.S. patent application 15/065,138 filed Mar. 9, 2016, which is a non-provisional application of and claims priority from U.S. patent application 62/130,113 filed Mar. 9, 2015, the specifications of which are all hereby incorporated herein by reference in their entireties.

BACKGROUND (a) Field

The subject matter disclosed generally relates to playing fields and more particularly to artificial sports and amusement playing fields. The subject matter disclosed may also relate to artificial turf surface of all kinds (i.e., artificial sports playing fields, artificial amusement playing fields, gymnasium surfaces, backyard surfaces and the like).

(b) Related Prior Art

The use of artificial or synthetic turf has been growing steadily in recent years. Artificial turf is a surface of synthetic fibers made to look like natural grass. It is most often used in arenas and fields for sports that were originally or are normally played on grass.

However, it is now being used in other applications such as, for residential lawns or landscapes, for pet areas, for child playgrounds, for golf courses and putting greens, on roofs, decks and patios as well.

The advantages of synthetic turf are numerous. For example, synthetic turf does not need to be cared as much as real grass. Moreover, synthetic turf is more durable.

There exist on the market numerous artificial or synthetic turf systems aiming to provide improved comfort, sufficient traction, and shock absorbent characteristics. For example, and now referring to PRIOR ART FIGS. 1A and 1B, there is shown a regular artificial turf system 10 which includes a sheet member 12 made of a flexible material and a plurality (substantially straight) fibers 14 upwardly extending from the sheet member 12. The plurality of fibers 14, which creates a carpet-like top layer, therefore includes a series of regularly spaced apart (or equally spaced) parallel rows of backstitches 16. For providing the shock absorbent characteristic, straight fiber support and sufficient traction for the desired sport to the artificial turf system 10, a plurality of rubber granules and/or sand (not shown, such as from recycled tires) are often disposed on the artificial turf system 10.

Even though the rubber granules and/or sand used in modern artificial synthetic turf tend to contain lower quantities of harmful substances, such as metal (e.g., lead and zinc), inorganic and organic compounds, it may significantly increase health problems for those playing/walking on it, it may significantly increase the surface temperature above the surface covering panel and it may lead to some other environmental problems. The infill also becomes compacted with time affecting directly shock absorption and traction of the artificial synthetic turf to the detriment of the players.

As for another example and referring now to PRIOR ART FIGS. 2A and 2B, there is shown an artificial turf system without infill 100 for installation over a receiving surface (not shown). The artificial turf system 100 includes a sheet member 102 made of a flexible material. The sheet member 102 defines a first surface or primary backing 104 for interfacing with the receiving surface and a second surface 106. The artificial turf system 100 further includes a plurality of primary yarns 108 made of straight fibers (monofilament, parallel fibrillated or fibrillated fibers) which are upwardly extending from the second surface 106 of the sheet member 102 and a plurality of secondary yarns 110 made of textured fibers or thatch fibers which are upwardly extending from the second surface 106 of the sheet member 102. The plurality of secondary yarns 110 are positioned on the sheet member 102 such as to intersperse with the plurality of primary yarns 108.

The plurality of secondary yarns 110 made of textured or thatch fibers represent less than 50% in weight (aka face weight) of the plurality of primary and secondary yarns 108, 110 taken together. Therefore, the straight fiber support, traction and shock absorbent characteristics are not optimized.

The plurality of primary and secondary yarns 108, 110 which creates together a carpet-like top layer 112 includes a series of regularly spaced apart (or equally spaced) parallel rows of backstitches 114, 116 tufted or knitted in straight line, in “zigzag” or in a S pattern. The series of regularly spaced apart parallel rows of backstitches 114, 116 include a series of regularly spaced apart parallel rows of backstitches 114 made of the plurality of primary yarns 108 and a series of regularly spaced apart parallel rows of backstitches 116 made of the plurality of secondary yarns 110, which are interspersed within the series of regularly spaced apart parallel rows of backstitches 114 made of the plurality of primary yarns 108.

The fact that the artificial turf system 100 combines both the plurality of primary yarns 108 made of straight fibers and the plurality of secondary yarns 110 made of textured or thatch fibers provides straight fiber support and player traction to the artificial turf system 100. However, according to this configuration, the straight fiber support, players traction and shock absorbent characteristic are not optimized.

There is therefore a need for improved no-infill artificial turf system that optimizes straight fiber support, player traction and shock absorbent characteristics and that would overcome the above-noted drawbacks.

SUMMARY

According to an embodiment, there is provided an artificial turf system for installation over a receiving surface, the artificial turf system comprising: a sheet member made of a flexible material, the sheet member defining a first surface for interfacing with the receiving surface and a second surface; primary yarns made of straight fibers backstitched in and threaded through the sheet member and upwardly extending from the second surface of the sheet member to a first elevation; and secondary yarns made of textured fibers backstitched in and threaded through the sheet member and upwardly extending from the second surface of the sheet member at a second elevation less than the first elevation defining a difference in elevation which is caused by a difference in texture between the primary yarns and the secondary yarns, wherein the secondary yarns are more rigid than the primary yarns, and wherein the primary yarns and the secondary yarns have ends which are cut after being threaded through the sheet member.

According to an aspect, the material used for the primary yarns is not the same material which is used for the secondary yarns, wherein the material used for the secondary yarns is more rigid than the material used for the primary yarns.

According to an aspect, the secondary yarns are textured, and wherein the textured fibers comprise crimped fibers.

According to an aspect, the secondary yarns represent more than 50% in weight of the primary and secondary yarns together.

According to an aspect, combined yarns composed of the primary and secondary yarns are backstitched in parallel equally spaced apart rows on the sheet material.

According to an aspect, the mass of the secondary yarns is greater than the mass of the primary yarns.

According to an aspect, the mass of the secondary yarns is in a range between 15,001 and 20,000 deniers.

According to an aspect, the primary yarns and the secondary yarns have respectively a length, and wherein the length of secondary yarns is greater than the length of primary yarns.

According to an aspect, a ratio of the second elevation over the first elevation is smaller than 75%.

According to an embodiment, there is provided an artificial turf system for installation over a receiving surface, the artificial turf system comprising: a sheet member made of a flexible material, the sheet member defining a first surface for interfacing with the receiving surface, and a second surface; a plurality of primary yarns being backstitched to the sheet member at primary backstitches, with the primary yarns raising from the primary backstitches away from the second surface to a first elevation; and a plurality of secondary yarns defining an underturf, the secondary yarns being backstitched to the sheet member at secondary backstitches, wherein the secondary backstitches are distributed in-between the primary backstitches, wherein the secondary yarns extend from the secondary backstitches up to a second elevation lower than the first elevation, wherein the secondary yarns extend sideways in random directions, and wherein the secondary yarns intertwine with other secondary yarns.

According to an aspect, the primary yarns comprise a lower section rising from the sheet member under the second elevation, and wherein the underturf provides a least partial support to the lower section of the primary yarns thereby impeding the lower section of the primary yarns from curving, bending or crooking.

According to an aspect, the primary yarns are made of straight fibers.

According to an aspect, the secondary yarns are made of curved fibers.

According to an aspect, the plurality of secondary yarns represents more than 50% in weight of the sum of the plurality of primary and secondary yarns together.

According to an aspect, the secondary yarns are more rigid than the primary yarns.

According to an aspect, the secondary yarns are textured, and wherein the textured fibers comprise crimped fibers.

According to an aspect, the primary yarns and the secondary yarns have respectively a length, and wherein the length of secondary yarns is greater than the length of primary yarns.

According to an aspect, a ratio of the second elevation over the first elevation is smaller than 75%.

According to an aspect, the primary yarns and the secondary yarns have respectively a width, and wherein the width of the primary yarns is greater than the width of the secondary yarns.

According to an aspect, the primary yarns and the secondary yarns have respectively a thickness, and wherein the thickness of the secondary yarns is equal or greater than the width of the primary yarns.

According to an embodiment, there is provided an artificial turf system for installation over a receiving surface. The artificial turf system comprises a sheet member made of a flexible material, the sheet member defining a first surface for interfacing with the receiving surface and a second surface. The artificial turf system further comprises a plurality of primary yarns made of straight fibers upwardly extending from the second surface of the sheet member and a plurality of secondary yarns made of textured fibers upwardly extending from the second surface of the sheet material and interspersed within the plurality of primary yarns. The plurality of secondary yarns represent more than 50% in weight of the plurality of primary and secondary yarns together.

According to an aspect, the plurality of secondary yarns are made of textured, thatched or crimped fibers.

According to another aspect, the primary and secondary yarns are backstitched in parallel equally spaced apart rows on the sheet material.

According to another aspect, combined yarns composed of the primary and secondary yarns are backstitched in parallel equally spaced apart rows on the sheet material.

According to another aspect, the artificial turf system with combined yarns composed of the primary and secondary yarns are backstitched in parallel equally spaced apart rows on the sheet material, with the rows forming a straight, S, or Z pattern.

According to another aspect, the artificial turf system with combined yarns composed of the primary and secondary yarns are backstitched in parallel equally spaced apart rows on the sheet material, with a distance separating two rows being ranged between 1/16″ and ½″.

According to another aspect, the sheet material is manufactured as one of a closed-weave woven, an opened-weave woven, leno weave cross weave or non-woven material.

According to another aspect, the thickness of the sheet member is substantially uniform and ranges between about 0.20 mm to about 2 mm.

According to another aspect, the mass of each of the plurality of primary yarns is ranged between about 2,000 and about 20,000 deniers.

According to another aspect, the plurality of secondary yarns are made of textured, thatched or crimped fibers and the mass of each of the plurality of secondary yarns is ranged between about 2,000 and about 20,000 deniers.

According to another aspect, the plurality of primary and secondary yarns are bound to the sheet member by heat, pressure or with Polyurethane.

According to another aspect, the primary yarns have a first length, the secondary yarns have a second length, and the second length is at least equal to the first length.

According to another aspect, the plurality of secondary yarns made of textured or thatch fibers represents one of: more than about 51%, more than about 55%, more than about 60%, more than about 65%, more than about 70%, more than about 75%, more than about 80%, more than about 85%, more than about 90% and more than about 95% in weight of the plurality of primary and secondary yarns together.

According to another aspect, at least one of a material in which is made the secondary yarns and a process performed on the secondary yarns render the secondary yarns more rigid than the primary yarns.

According to another aspect, the primary yarns are made of one of polyethylene, polypropylene, Polyamide, polyester (PET), and a combination of polyethylene and polypropylene.

According to another aspect, the secondary yarns are made of one of Polyamide, Polyester (PET), polyethylene, polypropylene, and a combination of polyethylene and polypropylene.

According to another aspect, the elevation of the secondary yarns with respect to the second surface is less than the elevation of the primary yarns with respect to the second surface.

According to another embodiment, there is provided an artificial turf system for installation over a receiving surface. The artificial turf system comprises a sheet member made of a flexible material, the sheet member defining a first surface for interfacing with the receiving surface and a second surface. The artificial turf system further comprises a plurality of primary yarns made of substantially straight fibers upwardly extending from the second surface of the sheet member and having a first elevation with respect to the second surface, and a plurality of secondary yarns upwardly extending from the second surface of the sheet material, the plurality of secondary yarns having a second elevation, lesser than the first elevation, with respect to the second surface. The artificial turf system has the plurality of primary and secondary yarns backstitched to the sheet material such as each backstitch is composed of a plurality of secondary yarns surrounding at least one primary yarn.

According to a further embodiment, there is provided an artificial turf system for installation over a receiving surface. The artificial turf system comprises a sheet member made of a flexible material, the sheet member defining a first surface for interfacing with the receiving surface and a second surface. The artificial turf system further comprises a plurality of primary yarns made of substantially straight fibers upwardly extending from the second surface of the sheet member and having a first elevation with respect to the second surface, and a plurality of secondary yarns upwardly extending from the second surface of the sheet material and interspersed within the plurality of primary yarns, the plurality of secondary yarns having a second elevation, lesser than the first elevation, with respect to the second surface. The plurality of secondary yarns represent more than 50% in weight of the plurality of primary and secondary yarns together.

Features and advantages of the subject matter hereof will become more apparent in light of the following detailed description of selected embodiments, as illustrated in the accompanying figures. As will be realized, the subject matter disclosed and claimed is capable of modifications in various respects, all without departing from the scope of the claims. Accordingly, the drawings and the description are to be regarded as illustrative in nature, and not as restrictive and the full scope of the subject matter is set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present disclosure will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

FIG. 1A is a schematic showing the top surface of an infilled artificial turf system in accordance with the PRIOR ART;

FIG. 1B is a schematic showing the bottom surface of the infilled artificial turf system in accordance with the PRIOR ART;

FIG. 2A is a schematic showing the top surface of a no-infill artificial turf system in accordance with the PRIOR ART;

FIG. 2B is a schematic showing another side (perpendicular to the side shown in FIG. 2A) of the no-infill artificial turf system of FIG. 2A in accordance with the PRIOR ART;

FIG. 3 is a schematic showing the top surface of an artificial turf system in accordance with an embodiment;

FIG. 4 is a schematic showing the side of the artificial turf system of FIG. 3;

FIG. 5 is a schematic showing a close-up view of the artificial turf system of FIG. 3;

FIG. 6 is a schematic showing the bottom surface of the artificial turf system of FIG. 3;

FIG. 7 is a schematic showing a close-up view of the sheet member of the artificial turf system; and

FIG. 8 is a schematic depicting the process of yarns through air jet spinning process.

It will be noted that throughout the appended drawings, like features are identified by like reference numerals.

DETAILED DESCRIPTION

In embodiments, there are disclosed artificial turf systems for applying on receiving surfaces.

Referring now to the drawings, and more particularly to FIGS. 3-6, there is shown a no-infill artificial turf 200 for installation over a receiving surface (not shown) in accordance with an embodiment. The no-infill artificial turf 200 includes a sheet member 202 made of a flexible material. The sheet member 202 defines a first surface, or primary backing 204 for interfacing with the receiving surface, and a second surface 206. The no-infill artificial turf 200 further includes a plurality of primary yarns 208 made of straight fibers (substantially straight fibers) which are upwardly extending from the second surface 206 of the sheet member 202 and a plurality of secondary yarns 210 made of textured fibers or thatch fibers which are upwardly extending from the second surface 206 of the sheet member 202. Because of their curly shape, the plurality of secondary yarns 210 position themselves automatically on the sheet member 202 in all direction and therefore result in surrounding the plurality of primary yarns 208.

The plurality of secondary yarns 210 made of textured or thatch fibers represents more than 50% in weight of the plurality of primary and secondary yarns 208, 210 taken together. More particularly, the plurality of secondary yarns 210 made of textured or thatch fibers may represent one of: more than about 51%, more than about 55%, more than about 60%, more than about 65%, more than about 70%, more than about 75%, more than about 80%, more than about 85%, more than about 90% and more than about 95% in weight of the plurality of primary and secondary yarns 208, 210 taken together.

The plurality of primary and secondary yarns 208, 210 which creates together a carpet-like top layer 212 includes a series of regularly spaced apart (or equally spaced) parallel rows of backstitches 214. These rows can be straight, in S or Z patterns, tufted or knitted. According to one embodiment, parallel rows of backstitches 214 of primary yarns 208 are alternated with parallel rows of backstitches of 214 secondary yarns 210. According to another embodiment, the series of regularly spaced apart parallel rows of backstitches 214 are made of a plurality of secondary yarns 210 surrounding or with at least one or a plurality of primary yarns 208. The combined yarn is therefore composed of both primary yarns 208 and secondary yarns 210. Regardless of the embodiment, the plurality of primary yarns 208 are therefore interspersed within the plurality of secondary yarns 210.

The fact that the no-infill artificial turf 200 combines both the plurality of primary yarns 208 made of straight fibers and the plurality of secondary yarns 210 made of textured or thatch fibers (more than 50% face weight of the plurality of secondary yarns is greater than the face weight of the plurality of primary yarns) provides improved straight fiber support, player traction and shock absorbent characteristics to the shock absorbent surface covering panel 200.

As shown in FIGS. 3-6, and as better shown in FIG. 6, the no-infill artificial turf 200 includes a plurality of backstitches 214 a. Each backstitch 214 a similarly includes a plurality of primary yarns 208 made of straight fibers with a plurality of secondary yarns 210 made of textured or thatch fibers, such as to allow the plurality of secondary yarns 210 made of textured or thatch fibers to represent more than about 50% in weight of the plurality of primary yarns 208 and secondary yarns 210 taken together.

Each backstitch 214 a may be separated by a backstitch distance. The backstitch distance may range between about 1/16″ and about ½″.

The sheet member 202 or several sheet members used together may include materials made of but not exclusively limited to Olefin (Polypropylene), Polyamide (Nylon), Polyethylene Terephalate (PET) virgin or a recyclable material, Polyestere Woven and non woven, cordura material either 100% or combination of these materials, manufactured in a closed-weave woven, an opened-weave woven, leno weave cross weave or non-woven material suitable to maximize ability to tuft, provide tuft bind of the primary and secondary yarns, provide dimensional stability, the hardness-flexibility ratio of the sheet member, provide penetration of the sheet by the secondary coating which is applied to the bottom of the sheet member and which can be made of polyurethane or latex or acrylic or some other material suitable to ask as a binder to hold the fibers in place to the sheet member or to allow the binding of the fibers to the sheet member by heat, pressure or with Polyurethane.

The thickness of the sheet member 202 is normally substantially uniform and may range between 0.20 mm to 2 mm.

The total mass (total of the mass of each filament) of each primary yarn filament 208 may be in a range between about 2,000 to about 20,000 deniers. The total mass of each primary yarn 208 may be in a range between about 2,000 and about 20,000 deniers depending on the denier per filament (DPF) and number of filaments in the yarn. Preferably, the total mass of each primary yarn filament 208 is ranged between about 4,000 and about 16,000 deniers.

The mass (total of the mass of each filament) of each secondary yarn 210 may be in a range between about 2,000 and about 20,000 deniers. The mass of each secondary yarn 210 may be in a range between about 2,000 and about 20,000 deniers depending on the denier per filament (DPF) and number of filaments in the yarn. Preferably, the total mass of each secondary yarn filament 210 is ranged between about 4,000 and about 16,000 deniers.

According to an embodiment, the mass of the secondary yarn filament 210 is greater than the mass of the primary yarn filament 208. According to an embodiment, the mass of the primary yarns is between about 2,000 and 19,999 deniers and the mass of the secondary yarns is between 2,001 and 20,000 deniers so long as the mass of the secondary yarn filament 210 is greater than the mass of the primary yarn filament 208.

According to an embodiment, the mass of each secondary yarn 210 may be in a range between 15,001 and 20,000 deniers depending on the denier per filament (DPF) and number of filaments in the yarn. Preferably, the total mass of each secondary yarn filament 210 is ranged between 15,001 and 16,000 deniers.

The material of the plurality of primary yarns 208 may include polyethylene, polypropylene, Polyamide, polyester (PET), Nylon, a combination of polyethylene and polypropylene and the like.

The shape and construction of the plurality of primary yarns 208 may include flat face fibers, monofilament fibers, monotape yarn and fibrillated yarn, polyfilament fibers, parallel fibrillated or fibrillated fibers and split fibers. The primary yarns 208 may be made from extrusion and take different shapes such as a rectangular cross-section ribbon, diamond, horseshoe, U, V, S shape or a flat rectangular general cross section with its shorter sides rounded. Its cross-section may feature one or more curved-convex projections for instance. When backstitched to the sheet member 202, the straight (or substantially straight) primary yarns 208 are set upwardly extending from the second surface to simulate the blades of grass of natural grass cover.

The material of the plurality of secondary yarns 210 may include Polyamide, Polyester (PET), polyethylene, polypropylene, Nylon, a combination of polyethylene and polypropylene and the like.

The shape and construction of secondary yarns 210 may include texturized monofilament, monotape yarn and fibrillated yarn.

According to an embodiment, the physical characteristics of the secondary yarns 210 are selected to obtain secondary yarns 210 that are more rigid than the primary yarns 208, therefore having the secondary yarns 210 providing the desired support while having the primary yarn 208 providing the desired texture. These desired physical characteristics may be commonly obtained through selection of a more rigid material for the secondary yarns 210 than for the primary yarns 208; that is, the material of the primary yarns 208 (selected from the list of materials disclosed herein for the primary yarns 208) is not the same material as the material for the secondary yarns 210 (selected from the list of materials disclosed herein for the secondary yarns 210). Alternatively, a process (physical or chemical) over the secondary yarns 210 modifying its physical characteristics may be used to obtain the desired rigidity.

The plurality of secondary yarns 210, while described herein as textured fibers or thatch fibers, may not require, according to one embodiment, to be textured. However, it is referred to herein as “textured” to distinguish itself in all embodiment from the primary “straight” yarn 208. The secondary yarns 210 may be made of a plurality of filiform formations arranged in turfs so as to provide a better simulation of the blades of grass of natural grass cover. The manufacturing of secondary yarns 210 to provide the desired shape and structure may be performed, for instance, by means of a heat, chemical or mechanical treatment before use through which the secondary yarns 210 are crimped. Accordingly, second yarns 210 may consist of yarns of at least the same length as the first yarns 208 that, when processed, result in the desired shorter looking secondary yarns 210.

Still referring to FIGS. 3-6, and more particularly to FIG. 4, the elevation 218 of the primary yarns 208 from the second surface is illustrated as greater than the elevation 220 of the secondary yarns 210 from the second surface regardless the real length of the primary and secondary yarns 208 and 210. Thereby the secondary yarns 210 provide the desired fiber support of the primary yarns 208, player traction and shock absorbing characteristics.

The tufting process of both primary and secondary yarns 208 and 210 can be performed by stitching both the primary and secondary yarns 208 and 210 concurrently, using the same needle. Alternatively, the primary yarns 208 and secondary yarns 210 may be stitched separately, using distinct needles. The latter result in parallel backstitches of primary yarns 208 and secondary yarns 210.

According to an embodiment, the tufting process includes threading the primary and secondary yarns 208 and 210 through the sheet member 202. Loops are thereby formed. The tops of the loops are then cut leaving the primary and secondary yarns 208 and 210 extending from the sheet member 202 with the end of each of the primary and secondary yarns 208 and 210 being cut.

It should be noted that while some prior art references, such as US Application publication number 2004/0253390 by Trafford indicate that their blades of different heights can be anchored into the pad in any manner desired including any way shown in the references which are listed therein, a person skilled in the art would know that the result that they wish to achieve is not possible by using the tufting techniques available at that time. That is, all tufting techniques cited by references in Trafford will cut the blades at the same height. This point is illustrated clearly by another reference (US Application publication number 2003/0099787 by Fink) which states: “the typical machine available for sports carpet tufting is capable of cutting only one pile height”. It is therefore not possible to have straight blades of different heights and different flexibility as in Trafford using conventional tufting techniques known at the time of Trafford which require the cutting of the loops resulting from the threading of yarn through a mat/sheet member.

According to an embodiment, both the primary and secondary yarns 208 and 210 are cut at the same height. The secondary yarns 210 being pre-stressed, textured, crimped, curled, curved or otherwise pre-shaped, they will return to a shorter height to form the underturf 300 described herein and leave the primary yarns 208 extending above the underturf 300 thus higher than the secondary yarns 210.

According to another embodiment, the loops forming the rows of primary yarns 208 and the loops forming the rows of secondary yarns 210 are cut using blades which are set at different heights. The selection of the heights of the cutting blades for each row of yarn is determined based on the desired rigidity and density for each of the rows.

According to another embodiment, the secondary yarns 210 are tufted in the sheet member 202 forming loops which are cut at a given height. The resulting carpet is then tufted again with primary yarns 208 forming loops which are cut at a given height which is different from the given height for the secondary yarns 210.

According to another embodiment, the primary yarns 208 are tufted in the sheet member 202 forming loops which are cut at a given height. The resulting carpet is then tufted again with secondary yarns 210 forming loops which are cut at a given height which is different from the given height for the primary yarns 208.

According to an embodiment, the length of the secondary yarns 210 is greater than the length of the primary yarns 208 while resulting in a height of the secondary yarns 210 on the sheet member 202 which is less than the height of the primary yarns 208.

Depending the tufting configuration selected, the tufting gauge can vary from about 3/16″ to about ¾″.

The no-infill artificial turf 200 as described above may increase protection for child in playgrounds, may provide improved players traction and shock absorbent characteristics for sport fields of all kinds, and may reduce the surface temperature above the panel. The plurality of secondary yarns 210 in sufficient quantity (more than 50% in weight) render the presence of rubber granules unnecessary to provide straight fiber support, while provide adequate traction for players and shock absorbent characteristics.

Referring back to FIGS. 2A-2B in comparison with FIGS. 4 and 5, the no-infill artificial turf 200, the present realization features primary yarns 208 backstitched to the sheet member 202 at locations, thereby defining through the backstitch interactions between the primary yarns 208 and the sheet member 202 a plurality of primary backstitches 302.

The secondary yarns 210 are also backstitched to the sheet member 202 at locations, thereby defining a plurality of secondary backstitches 304.

Accordingly, the sheet member 202 is scattered with a plurality of primary backstitches 302 and secondary backstitches 304, thereby having secondary backstitches 304 located in the space around the primary backstitches 302 or, in other words, having the secondary backstitches 304 located in-between primary backstitches 302.

One should understand from the expression “scattered” and “located in-between” that the secondary backstitches 304 may be located in any location relative to the primary backstitches 302, from having the secondary backstitches in rows aligned with rows of primary backstitches 302 (see FIG. 6) to having the secondary backstitches in a plurality of rows or random locations distributed between primary backstitches 302, with for example the rows of secondary backstitches 304 offset longitudinally and/or transversally relatively to the primary backstitches 302 or relative to neighbor secondary backstitches 304.

Referring particularly to FIGS. 4 and 5, the secondary yarns 210 are made of material having characteristics and shaped such as the secondary yarns 210 extending from the secondary backstitches substantially slightly upward and mainly sideward in order for the secondary yarns 210 as a whole to generate an underturf 300, or in other words a sub-layer of lower elevation (elevation 218) than the top elevation 220. The underturf 300, based on characteristics and/or shape of the secondary yarns 210 defining the underturf 300, provides a support for the primary yarns 208 under the lower elevation (elevation 218), thus about the primary backstitches 302. Practically, the secondary yarns 210 provides side pressure over the lower portion (under elevation 218) of the primary yarns 208 substantially on many (or all) directions of the primary yarns 208 such as impeding or hindering the lower portion of the primary yarns 208 to curve, bend or crook and thereby increase the efficient rigidity of the lower portion of the primary yarns 208 without requiring changes in the material, characteristics or structure of the primary yarns 208.

Further, to optimize the effect of the underturf 300, the secondary yarns 210 are configured to extend in random directions from the secondary backstitches 304 so as to intertwine with each other around and about the lower portion of the primary yarns 208, providing a “cushion” surrounding the primary backstitches 302 resulting in the “cushion” hindering deflection, curvature, bending and/or crooking of the lower portion of the primary yarns 208 as stated before.

Further, according to a realization, the secondary yarns 210 are curved such as when backstitched to the sheet member 202 the secondary yarns 210 raise from the secondary backstitches 304 and extend sideways in random directions to intertwine with each other. As a result, the lower section of the primary yarns 208 is interspersed with the secondary yarns 210 surrounding the primary yarns 208.

Further, according to a realization, the secondary yarns 210 intertwine with each other to form a substantially homogeneous underturf 300, wherein homogeneous refers to performing as a “cushion” having substantially similar characteristics over most of the surface of the sheet member 202.

Further, according to a realization, the secondary yarns 210 are more rigid than the primary yarns 208, wherein according to realizations, the secondary yarns 210 being more rigid is performed through one of selection of material for the primary yarns 208 and the secondary yarns 210, the shape of the secondary yarns 210, and characteristics associated with the secondary yarns through one chemical processing and physical processing of the secondary yarns 210.

Further, according to a realization, the weight of the plurality of secondary yarns 210 represents more than 50% of the weight of the sum of the plurality of primary yarns 208 and of the secondary yarns backstitched to a unit of sheet member 202.

Further, according to a realization, the length of secondary yarns 210 (when forced in a straight configuration) is greater than the length of primary yarns 208 (when forced in a straight configuration).

Further, according to a realization, the ratio of secondary backstitches 304 over the total number of backstitches (summing up primary backstitches 302 and secondary backstitches 304) per unit of sheet member 202 is at least 50%. According to a realization, this ratio is at greater than 50%. According to a realization, this ratio is at least greater than 66%.

Further, according to a realization, the ratio of the number of yarns per backstitch of the secondary backstitches over the primary backstitches is at equal to 100%. According to a realization, this ratio is greater than 100%. According to a realization, this ratio is greater than about 125%.

The ratio of the lower elevation over the top elevation is smaller than about 75%. According to a realization, this ratio is smaller than about 60%. According to a realization, this ratio is smaller than 50%. According to a realization, this ratio is smaller than about 40%.

Further, according to a realization, the primary yarns 208 and the secondary yarns 210 have respectively a color, and wherein the color of the primary yarns 208 differs from the color of the secondary yarns 210. For instance, the primary yarns 208 have a grass-green color while the secondary yarns 210 have a color that includes some shade of brown to more effectively recall a natural turf having a free grass on top and dying grass about the ground, with the layer of dying grass supporting the free grass in a raised position.

Further, according to a realization, the primary yarns 208 and the secondary yarns 210 have respectively a width, and wherein the width of the primary yarns 208 is greater than the width of the secondary yarns 210.

Further, according to a realization, the primary yarns 208 and the secondary yarns 210 have respectively a thickness, and wherein the thickness of the secondary yarns 210 is greater than the width of the primary yarns 208, thereby improving the support the secondary yarns 210 provide to the primary yarns 208.

In comparison, the no-infill artificial turf system 100 of FIGS. 2A and 2B of the PRIOR ART features secondary yarns 110 extending substantially upward from the sheet member 102 providing no support or low support to the section of the primary yarns having an elevation smaller than the elevation of the secondary yarns 108. Referring particularly to FIG. 2A, the secondary yarns 110, regardless their orientations, are not adapted to intertwine with each other to surround the primary yarns 108 and thereby provide support to the primary yarns 108 and thus the “cushion” discussed before.

According to a realization, the no-infill artificial turf 200 comprises only primary yarns 208 and secondary yarns 210 tuft side by side into a sheet member 202.

According to a non-limiting preferred realization, the primary yarns 208 are preferrable made of substantially straight fibers of polypropylene of about 5000 deniers. The primary yarns 208 have, typically, a pulled length extending from the sheet member 202 of between 2 and 3 inches, thus the no-infill artificial turf 200 having a corresponding top elevation (e.g., primary elevation 218) of between about 2 and about 3 inches.

According to a non-limiting preferred realization, the secondary yarns 210 are preferably made of highly textured fibers of polyamide, and more preferably nylon, wherein the secondary yarns 210 have undergone a series of tests to ensure that they fulfill a series of requirements that have been identified by the Applicant as mandatory to obtain the highly textured yarns (in opposition to textured yarns) to result in a no-infill artificial turf 200 fulfilling desired requirements without the necessity to add infilled to the artificial turf system 100.

According to a manufacturing perspective, the secondary yarns 210 are hydrophilic fibers, preferably nylon, having undergone a texturing process, and preferably an air jet processing under controlled environment, wherein the resulting yarn is a highly textured hydrophilic yarn having improved characteristics that none of a hydrophobic fiber having undergone a similar process or a hydrophilic fiber having undergone another texturing process, such as a knit-deknit process, would result in a fiber having similar characteristics.

Accordingly, the nylon of the secondary yarns are highly textured in preparation of its use in the manufacturing of the no-infill artificial turf 200. An air jet spinning process is used. It is a pneumatic method which consists of passing a drafted strand of fibers through one or two fluid nozzles located between the front roller of a drafting system and a take up a device (see FIG. 8 for example). This has been shown to be superior to methods employing a single nozzle to spin the yarn.

For teaching purposes, the air jet spinning may be described as follow. The drafting system drafts the input material into a ribbon-like form with parallel fibers. Air is injected into the two nozzles at high pressures, which cause swirling air streams in opposite directions.

Sliver is fed into the machine and is further drawn out to the final count and twist is inserted by means of a rotating vortex of high pressured air. The resultant yarn is cleared of any defects and wound onto packages ready for use in fabric formation.

Some fibers, particularly those at the edges of the ribbon, will not be subjected to the full twisting action imparted to the main body of fibers by the downstream air-jet. Hence they receive less twist than those fibers in the main bundle. When the yarn gets untwisted in the downstream of the twister, the low twist edge fibers get untwisted to a greater degree than their original twist. Therefore they are given a true twist in the direction opposite to that of the upstream twist.

The main body of the strand will be untwisted into parallel fibers, forming the core and these will be wrapped around by the edge fibers forming the wrapper fiber layer or the sheath, thus forming a fasciated yarn.

The function of the back nozzle is to enhance the cohesion of the strand thus giving greater yarn strength. Since the direction of airflow in the back nozzle is opposite to that of the front nozzle, the back nozzle tends to untwist the wrapper fibers as they are formed inside the front nozzle. This increases the length of wrapping, thus improving the yarn cohesion.

The air-jet spun yarn consists of an untwisted core of parallel fibers and a surface wrapping of fibers. The core fibers account for approximately 85-95% of the yarn mass. The surface wrapper fibers are helical in nature unlike the wrapper fibers in the rotor yarn.

The wrapper fibers are not uniformly distributed over the length; sometimes they are more on the surface and sometimes very few are on the surface. Their frequency and tightness being influenced by the fiber physical properties and the spinning process parameters. “The high level of constriction of the straight core fibers by the surface wrapper fibers results in high bending modulus of air-jet yarns”.

The tensile strength is lower than that of rotor and ring yarns. More wrapping turns give better yarn strength, but at the same time, higher wrapping frequency leads to higher bending rigidity and lower compressive softness.

The untwisted core fibers contribute to the very low snarling tendency of the air-jet spun yarns. Surface fibers twisted lightly around the core cause the yarn to be well suited for use as filling in air-jet weaving machines, as it can be propelled across the shed more quickly. The lack of twist in the air-jet yarn core is believed to contribute to the low pilling propensity of these yarns.

The pills can still be created from abrasion, but they are not locked into the structure because of the absence of the twist. Pills break away easily after they are formed. Also, it has been shown that as the number of the core fibers increases, the proportion of the protruding fibers is reduced, resulting in lower yarn hairiness.

According to realization, the air-jet textured yarn may be subject to further processing before being tufted in the sheet member 202.

Furthermore, as explained in https://core.ac.uk/download/pdf/288373235.pdf, the process of texturing the yarns using an air-jet process allows to obtain textured yarns with texture characteristics determined by the instability, linear density, and strength, together with structural properties such as loop size, loop frequency, and degree of entanglement, that may not be obtained with a method such as the knit-deknit process of Auguste.

The typical yarn properties exhibited by the air jet textured yarns are good tenacity, good evenness, low snarling tendency, and low tendency to pilling, high stiffness, and high shrinkage. Such properties allow the air jet textured nylon to be used for the secondary yarns 210 to be tufted in the sheet member 202 with primary yarns 208 to form a no-infill artificial turf 200 wherein the secondary yarns 210 provide the necessary support to the primary yarns 208 to avoid the necessity to add infill to the yarns 208 and 210 to obtain the desired no-infill artificial turf 200.

It is worth noting, as stated in the article Air Jet Texturising—A Versatile Process of Texturising by M. Y. Gudiyawar Neha Hinge, The Textile Review, January, 2012, that:

“Air textured yarn is very bulky with permanent crimps and loops. Interlacing of filaments in the jet can cause the loops to be locked into the yarn, so that twist is unnecessary. Loop frequency, loop dimensions, loop stability and physical bulk are the important characteristics of air jet textured yarns.

Yarns produced by the air-jet texturising are totally different structures in that they much more closely simulate spun yarn structures. Whereas the bulkiness of the stretch yarns decreases with the degree of the tension imposed on them, the form of air-textured yarns can be made to remain virtually unchanged at loads corresponding to those normally imposed in fabric production and during wear. This is due to the locked-in entangled loop structure attributed to air jet textured yarns.”

Further, by controlling process parameters, and particularly the overfeed, fibers of polyamide may be subject to air jet texturing to obtain the desired characteristics for the secondary yarns 210 fulfilling the requirements for the no-infill artificial turf 200.

Accordingly, the hydrophilic fibers are air jet textured while the knit-deknit process as known nowadays and as described in Auguste (U.S. Pat. No. 6,321,427) teaches the use of an autoclave to heat the fibers with the autoclave set at temperature of between about 230- and 290-degrees Fahrenheit. Such knit-deknit process does not provide the desired results.

The secondary yarns 210 are of over 5000 deniers and preferably about 6000 deniers. The secondary yarns 210 consist in yarns, when pulled and stretched, that are of about the same length as the primary yarns 208. Once cut at an equivalent height of the primary yarns 208, they retract into their normal relaxed length of about 40% of their original length. According to realizations, the relaxed length of the secondary yarns 210 is at most 75%, preferably at most 60%, and preferably at most 50%, and even more preferably about 40% of its pulled length.

It is to be noted that the secondary yarns 210 are tested for extension and restauration characteristics before use. Acceptable secondary yarns 210 for this purpose must fulfill a test with the yarns being classified in highly textured yarns. For the present description, textured yarns according to industry standards are fibers that, according to a modified ASTM D4031 method, wherein the yarns are imposed a standard weight and are calculated a value of bulk shrinkage of at most 15%. Highly textured yarns are yarns that according to the same testing method are calculated a bulk shrinkage of at least 20%, and preferably at least 25%, and more preferably about 30%.

The resulting no-infill artificial turf 200 further undergoes a compression test of the yarns 208 and 210 tufted to the sheet member 202 undergoing a compression from 12 mm to 10 mm with a mass of 22 kg (2.2 kg per square mm) placed over the no-infill artificial turf 200.

Accordingly, the present no-infill artificial turf 200 fulfils the following standard tests without the use of infill material, while these tests require for other artificial turfs the use of infill material and/or the use a padding layer to be within acceptable limits. These tests are:

1. A chock absorption (Gmax, aka slow down rate in n-times the gravitation acceleration) with the no-infill artificial turf 200 mounted directly on a receiving surface (without the use between the receiving surface and the no-infill artificial turf 200 of a padding layer such as the padding layer described in U.S. Pat. No. 8,858,349 from the Applicant) of less than 200G according to the testing method ASTM F355, and even closer to 190G, and with such an padding layer a result of between 80 and 130G, which is about the chock absorption of a natural turf in the ideal conditions (between 90 and 110G).

2. Force reduction according to ASTM F3189 of more than 50% without the use of any infill material and any padding layer. According to realizations, the measure of force reduction may be up to 52%, and even up to 54-55%.

3. Bulk test according to ASTM D4031 requiring a result of over 30%. According to realizations, the test result is over 30% and more preferably over 40% and may even result to about 50%.

The secondary yarns 210, when made of nylon, are designed to provide a tensile strength (measured according to ASTM D2256-06) of about 15N per filament.

The primary yarns 208 and secondary yarns 210 are tufted side-by-side to a sheet member 202 on which, after the tufting, the opposed side, aka the underside, the underside is processed with a curable material, e.g., urethan, and with heat applied to the underside to cure the urethan to the underside. The underside is slowly heated over a conveyor with a heat temperature that is preferably under 85 degrees Celsius.

The density of the resulting no-infill artificial turf 200, without the addition of infill, is at least 2000 gram per square meter, and preferably about 2200 gram per square meter, resulting in a no-infill artificial turf system 100 able to remain stable and in place regardless of the external forces undergone as long as the external forces are within the range of normal use.

Th drainage characteristics of the no-infill artificial turf 200, with draining punctures made over the sheet member 202, is of at least 500 mm of water per hour according to method EN 12216, without affecting negatively other characteristics of the no-infill artificial turf 200 (see tests discussed before). According to realizations, the absence of infill material combined with the characteristics of the yarns 208 and 210, and of the sheet member 202, provide drainage characteristics of more than 750 mm of water per hour, more than 1000 mm of water per hour, more than 1500 mm of water per hour, and that can even reach 2000 mm of water per hour.

According to a preferred realization, the sheet member 202 is made of a combination of at least two layers, one of woven polypropylene, and another of one of glass fiber or of polyester, wherein the combination provides the desired characteristics comprising stability within a desired range to face temperature drops and temperature increases. According to a realization, the sheet member 102 comprises more than two layers, wherein the extra layers are made of any of the before listed materials.

As a result, the no-infill artificial turf 200 resulting from that process may fulfill all the requirements for sports field use without the use of infill material. The no-infill artificial turf 200 may further be installed directly on a receiving surface and fulfill the requirements, or may optionally be installed over a under padding to obtain a rate of chock absorption of a system that very closely mimics the characteristics of natural turf.

Therefore, according to a realization, of the no-infill artificial turf 200 is installed on a gravel surface, another natural surface, or a concrete surface.

According to other realizations, the no-infill artificial turf 200 is installed over a under padding layer itself previously installed over one of a gravel surface, another natural surface, or a concrete surface, where drainage characteristics are designed to match the drainage characteristics of the no-infill artificial turf 200 when installed outdoor.

It is worth noting that, according to a preferred realization, the no-infill artificial turf 200 comprises a compilation of hydrophobic material for the primary yarns 208 that are extending the highest, and of hydrophilic material for the secondary yarns 210.

While preferred embodiments have been described above and illustrated in the accompanying drawings, it will be evident to those skilled/in the art that modifications may be made without departing from this disclosure. Such modifications are considered as possible variants comprised in the scope of the disclosure. 

1. An artificial turf adapted to be installed free of infill material, comprising: a sheet member comprising a first surface and a second surface; first yarns made of straight fibers tufted in the sheet member, and having a first pulled length; second yarns made of textured fibers tufted in the sheet member, having a second pulled length equivalent to the first pulled length, and having a relaxed length of at maximum 50% of the first pulled length, wherein the sheet member, the first yarns and the second yarns sum up to the artificial turf having a weight density of at least 2000 gram per square meter.
 2. The artificial turf of claim 1, wherein the second yarns are hydrophilic textured fibers representing a minimum of 50% of the weight density of the artificial turf, and wherein the second yarns have a tensile strength of a minimum of 15N per filament.
 3. The artificial turf of claim 1, further comprising a curable material to be applied to the first surface of the sheet member, wherein the sheet member, the first yarns, the second yarns and the curable material are heated together when curing the curable material; and wherein the relaxed length of the second yarns tufted in the sheet member is at maximum 50% of the first pulled length prior to curing of the curable material.
 4. The artificial turf of claim 1, wherein chock absorption characteristics of the artificial turf is of a value smaller than 200G according to ASTM F355 method of testing.
 5. The artificial turf of claim 1, wherein each the first yarns and second yarns have a linear density of between about 4500 and about 7500 deniers, and wherein the linear density of the first yarns is lower than the linear density of the second yarns.
 6. The artificial turf of claim 1, wherein the sheet member made of a layer of woven polypropylene and at least one extra layer made of one of fiber glass and polyester, wherein the artificial turf comprises a curable material to be applied to the first surface of the sheet member, wherein the sheet member, the first yarns, the second yarns and the curable material are heated together when curing the curable material, wherein each the first yarns and second yarns have a linear density of between about 4500 and about 7500 deniers, and wherein the linear density of the first yarns is lower than the linear density of the second yarns.
 7. The artificial turf of claim 1, wherein the yarns of the artificial turf comprise a mix of hydrophobic material and hydrophilic material.
 8. An artificial turf adapted to be installed free of infill material, comprising: a sheet member comprising a first surface and a second surface; exclusively first yarns and second yarns, wherein the first yarns are made of straight fibers tufted in the sheet member, and having a first pulled length, and wherein the second yarns are made of textured fibers tufted in the sheet member, having a second pulled length equivalent to the first pulled length; and a curable material to be applied to the first surface of the sheet member, wherein the sheet member, the first yarns, the second yarns and the curable material are heated together when curing the curable material, wherein chock absorption characteristics of the artificial turf is of a value smaller than 200G according to ASTM F355 method of testing.
 9. The artificial turf of claim 8, wherein chock absorption characteristics of the artificial turf is of a value smaller than 130G according to ASTM F355 method of testing when the first surface of the sheet member is installed over a padding layer.
 10. The artificial turf of claim 8, wherein once the curable material cured, wherein the sheet material undergoes a puncture process, and wherein drainage characteristics of the artificial turf is at least 750 mm of water per hour.
 11. The artificial turf of claim 8, wherein the sheet member, the first yarns and the second yarns sum up to the artificial turf having a weight density of at least 2000 gram per square meter.
 12. The artificial turf of claim 8, wherein each of the first yarns and second yarns have a linear density of between about 4500 and about 7500 deniers, and wherein the linear density of the first yarns is lower than the linear density of the second yarns.
 13. The artificial turf of claim 8, wherein the yarns of the artificial turf comprise a mix of hydrophobic material and hydrophilic material.
 14. The artificial turf of claim 8, wherein the first length is not shorter than about 2 inches and not longer than about 3 inches.
 15. An artificial turf adapted to be installed free of infill material, comprising: a sheet member comprising a first surface and a second surface; first yarns made of straight fibers tufted in the sheet member, and having a first pulled length; second yarns made of textured fibers tufted in the sheet member, having a second pulled length equivalent to the first pulled length, a curable material to be applied to the first surface of the sheet member, wherein the sheet member, the first yarns, the second yarns and the curable material are heated together when curing the curable material; and wherein the second yarns tufted in the sheet member have a relaxed length of at maximum 50% of the first pulled length prior to curing of the curable material.
 16. The artificial turf of claim 15, wherein the sheet member, the first yarns and the second yarns sum up to the artificial turf having a weight density of at least 2000 gram per square meter.
 17. The artificial turf of claim 15, wherein the second yarns are hydrophilic textured fibers representing a minimum of 50% of weight density of the artificial turf, and wherein the second yarns have a tensile strength of a minimum of 15N per filament.
 18. The artificial turf of claim 15, wherein chock absorption characteristics of the artificial turf is of a value smaller than 200G according to ASTM F355 method of testing.
 19. The artificial turf of claim 18, wherein chock absorption characteristics of the artificial turf is of a value smaller than 130G according to ASTM F355 method of testing when the first surface of the sheet member is installed over a padding layer.
 20. The artificial turf of claim 15, wherein each the first yarns and second yarns have a linear density of between 4500 and 7500 deniers, and wherein the linear density of the first yarns is lower than the linear density of the second yarns. 